Let's Make Robots!

The Stag Mark 2

autonomous navigation of unknown terrain



So I have made some significant progress in the Stag project and I thought it was time to post it.


The quad in my last post was Stag Mark 1, Mark 2 is almost twice the size of its predecessor and now 100% more autonomous. Mark 2 uses a combination of HerkuleX DRS-0101 and DRS-0102 servos from Dongbu Robot to get around and it can now see with an ASUS Xtion PRO LIVE camera. The controller is still a PandaBoard ES running Ubuntu Server 12.04 and the body was printed on a RepRap Mendel.


Mark 2 also has an IMU and foot sensors it uses to autonomously traverse unknown terrain. It is also (somewhat) capable of recovery if it losses footing.


The video included in this post shows the Stag navigating an obstacle course and also shows some of the work I have been doing on a dynamically stable trotting gait.


For (slightly) more information visit my site www.stagrobotics.com or just ask here.


Questions and comments encouraged!



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Very nice one :)

Qiuck question: did you use pressure sensors for the legs are or do the sensors only have two states?

The feet are just spst switches with rubber NERF bullet tips attached so yes 2 states. The normal force is estimated using the servo torque although this is semi unreliable. I'm currently checking out my options for a new contact force sensing system.

I like how the front knees are able to invert. I would think that helps a lot with terrain adaptation and gait stability. Keep up the great work. Looking forward to updates about the vision system.

Sorry, double post...deleted.

Excellent robot. You should have a look at this http://letsmakerobots.com/node/29925

I really like the nature inspired leg design. 

Nice job. 

The trotting gait is very realistic.  I can only imagine the amount of time you have in these to get this to where you are.  Surprising how much time it takes...


I was planning on building a similar quadripedal robot but was planning on using only 2 DOF per leg. Can I know from your experience whether the gait would remain stable if I were to eliminate the hip abduction joint and make it rigid?

Also, do you use your foot sensors to only detect contact with the ground or measure the ground forces?

Thanks a ton!